Change API definitions from 'WIP' to 'Draft'

What does this MR do?

As part of the work to eradicate WIP in favor of Draft, this small merge request updates user-facing definitions to use the word Draft instead of WIP. Backend MRs like these take longer than a standard documentation-only merge request, so I'll continue to work on cleaning out the mentions of WIP in our documentation in a different merge request.

• Related to #231502 (closed) which tracks the total need
• Related to #321892 (closed) which identifies that wip is still used in our API, which means wip appears in our documentation in a way that I cannot fix on my own

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #231502 (closed)